Two-dimensional defective black phosphorus/BiVO₄ nanoheterojunctions for molecular nitrogen activation

Solar-driven transfer of nitrogen into ammonia is still challenging as a result of the strong dipole moment of the NN triple bond. Molecular nitrogen activation to construct the reactive active nitrogen species (RNS) is the key aspect for the highly efficient solar N₂ conversion. Herein, we selected black phosphorus-BiVO₄ (BP-BiVO₄) as a model system to clarify the significance of the inherent defective state to the molecular nitrogen activation over the formed heterojunctions. Oxygen vacancies (OVs) induced BP-BiVO₄ heterojunctions (OV-BP-BiVO₄) were controllably fabricated through quasi-reverse-emulsion approach. OVs in the lattice of the heterojunctions were introduced by the pulsed laser irradiation, which to a great extent determined the kinetics, energetics, and mechanism of the photocatalytic N₂ reduction. Systematic experiments revealed that the optimized heterojunction interfaces and rich OVs states led to superior ability in the activation of active molecular nitrogen (N₂ → RNS → NH₃). This work brightens defective and interfacial perspectives for the construction of efficient heterojunctions to produce reactive nitrogen species with high photocatalytic activity, and extend their potentials to a wide variety of other inorganic/organic transformations.